There are some well known systems employed for in-wheel motors: a direct drive system that transmits output rotation of the motor to the wheel assembly without reducing the speed at all; and a reducer-combined system that transmits output rotation of the motor to the wheel assembly while reducing the speed by a reducer. Conventional in-wheel motors of a reducer-combined system are disclosed in, for example, Japanese Unexamined Patent Application Publication Nos. 2013-209016 (PTL 1) and Japanese Patent No. 5677142 (PTL 2). The in-wheel motor disclosed in PTL 1 includes a parallel double-shaft gear reducer having an output shaft and an input shaft extending in parallel with each other. The in-wheel motor disclosed in PTL 2 includes a parallel triple-shaft gear reducer having an output shaft, an intermediate shaft, and an input shaft extending in parallel with one another.